Driving device for motor driven vehicles

ABSTRACT

A driving device for motor driven vehicles having an endless track with meshing holes, front and rear sprocket wheels meshing with the endless track, either of said sprocket wheels driven by the engine of the vehicle to drive in turn the endless track, a plurality of suspension wheel means and closing means for shutting the meshing holes of the endless track, the closing means held by the suspension wheel means, thereby, preventing snow from getting inside the endless track to render safe and smooth operation of the device.

United States Patent [191 Masaoka M lMarch 13, 1973 DRIVING DEVICE FORMOTOR DRIVEN VEHICLES [75] Inventor: Yutaka Masaoka,Hamakita, Japan [73]Assignee: Yamaha Hatsudoki Kahushiki Kaisha, Shizuoka-ken, Japan 22Filed: Sept. 24, 1970 21 Appl. No.: 74,984

[30] Foreign Application Priority Data Sept. 29, 1969 Japan ..44/92428[52] US. Cl. ..l80/5 R, 305/24 [51] Int. Cl. ..B62m 27/02 [58] Field0fSearch....305/Il,12,13, 24, 27, 35 EB; 180/5 [56] References CitedUNITED STATES PATENTS Lamb ..305/27 Eh-axi 3,527,506 9/! 970 Erickson..305/27 Primary Examiner-Richard J. Johnson Attorney-Berman, Davidsonand Berman [57} ABSTRACT A driving device for motor driven vehicleshaving an endless track with meshing holes, front and rear sprocketwheels meshing with the endless track, either of said sprocket wheelsdriven by the engine of the vehicle to drive in turn the endless track,a plurality of suspension wheel means and closing means for shutting themeshing holes of the endless track, the closing means held by thesuspension wheel means, thereby, preventing snow from getting inside theendless track to render safe and smooth operation of the device.

6 Claims, 2 Drawing Figures PATENTEUHAR 1 3197s m 2 a: x E

' INVENTOR W/ m KA MA 84 (MA,

ATTORNEYS DRIVING DEVICE FOR MOTOR DRIVEN VEHICLES The present inventionrelates to a driving device for motor driven vehicles such assnowmobiles, or tractors, and the like, and more particularly to animproved driving device having an endless track driven by power takenfrom the vehicle engine by means of a sprocket wheel positioned on thefront or rear portion of the body of the vehicle, each of the sprocketwheels meshing with the endless track, and a plurality of suspensionwheels suspended resiliently under the body of the vehicle to ensuregood engagement of the outer, or ground'touching, face of the endlesstrack with the ground.

Small snowmobiles of small size and the like heretofore known, havegenerally provided been installed with a driving device comprising afront sprocket wheel positioned under the front portion of the body ofvehicle and driven by the power taken from the vehicle engine, a rearsprocket wheel joumalled at the rear portion of the body, an endlesstrack meshing with and driven by one of said sprocket wheels, and aplurality of suspension wheels provided under the body of the vehicle soas to hold the endless track in contact with the ground. In using ofthis type of vehicle, a major disadvantage is that snow gets inside theendless track through the meshing holes at the lower, or groundtouchingportion. This particularly occurs on roads covered with freshly fallensnow, and the snow which enters the track becomes a large mass. Thiscauses the endless track to bulge outwardly, to disengages the meshbetween the sprocket wheels and the endless track and causes the upperportion of the endless track to touch the bottom of the body of thevehicle, resulting in unsafe erratic operation.

The most important object of the present invention is, therefore, toprovide an improved driving device for a small snowmobile having anendless track and sprocket wheels joumalled at the front and rearportions of the body of the vehicle to drive the endless track, saidendless track being characterized by closing means installed resilientlyunder the body of the vehicle against the meshing holes for the sprocketwheels at the lower, or ground-touching, portion of the endless track soas to prevent snow from getting inside the endless track through themeshing holesthereofwhen the vehicle runs on snowy roads.

The second important object of the present invention is to provide animproved driving device, having the above described characteristics,wherein the closing means to shut off said meshing holes are adapted atleast at the front head portion of the endless track when the vehicleruns forward, to more efficiently prevent snow from getting into theinside of the endless track through the meshing holes thereof.

The third important object of the present invention is to provide animproved driving device, having the above described characteristics,wherein said closing means are mounted by resilient members on thesuspension axles of the suspension wheels and are suspended resilientlyunder the body of the vehicle to press down the endless track intocontact with the ground, thereby enabling the closing means to be ofsimple construction and have stable and sure operation.

The novel features that are considered to be characteristic of theinvention are set forth with particularity in the appended claims. Theinvention, itself, however, both as to its organization and its methodof operation, together with additional objects and advantages thereof,will best be understood from the following description of specificembodiments when read in connection with the accompanying drawings,wherein like reference characters indicate like parts throughout theFigures.

In the drawings:

FIG. I is a longitudinal cross-sectional view of a driving device for asmall snowmobile in accordance with the present invention;

FIG. 2 is an enlarged cross-sectional view taken on line 22 of FIG. 1,with the body broken away for convenience of illustration.

Referring now more specifically to the drawings, an embodiment of thepresent invention comprises an endless track 1 provided with a number ofmeshing holes 6 arranged longitudinally along the center line of thewidth thereof, a front sprocket wheel 2 driven by a driving shaft 4journalled at the front portion of the body B of the vehicle, and a rearsprocket wheel 3 secured on an idler shaft 5 at the rear portion of thebody. The endless track 1 is stretched over the front and rear sprocketwheels 2 and 3, the teeth 2a and 3a of which mesh with the meshing holes6 of the endless track 1 to drive the endless track 1 by rotation of thefront sprocket wheel 2. A plurality of suspension wheels 7 are alljoumalled rotatably on axles 9 or 9' which are suspended swingably onshafts 8 by means of sleeves 11 or 11 and arms 10 or 10', said shafts 8being transversally fixed under the body of the vehicle. Torsion springs12 are coiled round the sleeves l1 and bias each pair of the suspensionwheels 7 downward and inward towards each other, which makes thesuspension wheels 7 press the endless track against the ground and actas shock absorbers for the body of the vehicle. U- shaped brackets 17are joumalled swingably on the central portions of the shafts 8 throughshaft bearing members 19. Bow shaped leaf springs 14 are fastened on thebottoms of the U-shaped brackets 17 with bolts 18a and nuts 18b. Thefront and rear ends of the bow shaped leaf springs 14 being securedrespectively to the front and the rear ends of closing plates 13 bymetal fittings 16 on closing plates 13 and holding pins 15. The closingplates 13 slide on and shut the meshing holes 6 of the endless track 1resiliently through the force of the bow shaped leaf springs 14 at theintermediate spaces between pairs of suspension wheels 7 on the innerside of the endless track 1. As shown in FIG. I, it is most desirablethat the frontmost closing plate 13a have an extended front section,giving it a somewhat shaped configuration.

, When a snowmobile provided with the above described improved drivingdevice runs on roads covered with fresh snow, the closing plates 13prevent most snow from getting into the inside of the endless track 1through the meshing holes 6 facing the ground.

Now it should be clear that although the above preferred embodimentadopts a plurality of closing plate 13, good efficiency in keeping snowout of the inside of the endless track 1 is obtainable substantiallywith the substantially L-letter shaped closing plate 13a positioned atthe front of the track.

Although certain specific embodiments of the present invention have beenshown and described, it is obvious that many modifications thereof arepossible, the differences of the styles and constructions of the endlesstrack, the suspension wheels, and so forth. The present invention is,therefore, not intended to be restricted to the exact showing of thedrawings and description thereof, but is considered to includereasonable and obvious equivalents.

What is claimed is:

1. In a driving device for a motor driven snow vehicle comprising avehicle body, a pair of power driven toothed sprocket wheels journaledon opposite ends of said body, a flexible endless track engaged oversaid sprocket wheels and having a plurality of spaced apart holes formedtherein for meshing with the teeth of said sprocket wheels, theimprovement comprising:

a. a transverse shaft fixedly secured to said body in underlyingrelation thereto;

a pair of arms journaled on said shaft;

resilient means biasing said arms downwardly and inwardly toward eachother;

. an axle secured to the lower end of each of said arms;

. a trackengaging wheel journaled on each of said axles;

. a bracket journaled on and depending from said shaft;

. a leaf spring mounted on the lower end of said bracket; and

. a covering plate secured to said leaf spring and biased into holecovering contact with the inner face of said track.

2. In a driving device for a motor driven vehicle comprising a vehiclebody, a pair of power driven toothed sprocket wheels journaled on frontand rear ends of said body, a flexible endless track engaged over saidsprocket wheels and having a plurality of longitudinally spaced apartholes formed therein for meshing with the teeth of said sprocket wheels,the improvement, comprising:

a. a transverse shaft fixedly secured to said body;

b. a pair of frontwardly and rearwardly extending arms journaled on saidtransverse shaft; first resilient means biasing said arms downwardly andinwardly toward each other;

track-engaging suspension wheels mounted on said arms;

. a plurality of closing plates engaging with said track to cover saidholes at the inside of the lower run of said track and supported underand by said body along the longitudinal line on which said holes arelocated; and

f. second resilient means comprising separate spring means for each ofsaid closing plates mounted on the lower portion of said body for urgingsaid closing plates onto the inner face of said track.

3. A driving device for a motor driven snow vehicle as set forth inclaim 2 wherein the closing plate closest to the forward end of saidvehicle is substantially L- shaped.

4. A driving device for a motor driven snow vehicle as set forth inclaim 2 wherein each of said spring means is swingably suspended fromsaid transverse shaft.

5. A driving device for a motor driven snow vehicle

1. In a driving device for a motor driven snow vehicle comprising avehicle body, a pair of power driven toothed sprocket wheels journaledon opposite ends of said body, a flexible endless track engaged oversaid sprocket wheels and having a plurality of spaced apart holes formedtherein for meshing with the teeth of said sprocket wheels, theimprovement comprising: a. a transverse shaft fixedly secured to saidbody in underlying relation thereto; b. a pair of arms journaled on saidshaft; c. resilient means biasing said arms downwardly and inwardlytoward each other; d. an axle secured to the lower end of each of saidarms; e. a track-engaging wheel journaled on each of said axles; f. abracket journaled on and depending from said shaft; g. a leaf springmounted on the lower end of said bracket; and h. a covering platesecured to said leaf spring and biased into hole covering contact withthe inner face of said track.
 1. In a driving device for a motor drivensnow vehicle comprising a vehicle body, a pair of power driven toothedsprocket wheels journaled on opposite ends of said body, a flexibleendless track engaged over said sprocket wheels and having a pluralityof spaced apart holes formed therein for meshing with the teeth of saidsprocket wheels, the improvement comprising: a. a transverse shaftfixedly secured to said body in underlying relation thereto; b. a pairof arms journaled on said shaft; c. resilient means biasing said armsdownwardly and inwardly toward each other; d. an axle secured to thelower end of each of said arms; e. a track-engaging wheel journaled oneach of said axles; f. a bracket journaled on and depending from saidshaft; g. a leaf spring mounted on the lower end of said bracket; and h.a covering plate secured to said leaf spring and biased into holecovering contact with the inner face of said track.
 2. In a drivingdevice for a motor driven vehicle comprising a vehicle body, a pair ofpower driven toothed sprocket wheels journaled on front and rear ends ofsaid body, a flexible endless track engaged over said sprocket wheelsand having a plurality of longitudinally spaced apart holes formedtherein for meshing with the teeth of said sprocket wheels, theimprovement, comprising: a. a transverse shaft fixedly secured to saidbody; b. a pair of frontwardly and rearwardly extending arms journaledon said transverse shaft; c. first resilient means biasing said armsdownwardly and inwardly toward each other; d. track-engaging suspensionwheels mounted on said arms; e. a plurality of closing plates engagingwith said track to cover said holes at the inside of the lower run ofsaid track and supported under and by said body along the longitudinalline on which said holes are located; and f. second resilient meanscomprising separate spring means for each of said closing plates mountedon the lower portion of said body for urging said closing plates ontothe inner face of said track.
 3. A driving device for a motor drivensnow vehicle as set forth in claim 2 wherein the closing plate closestto the forward end of said vehicle is substantially L-shaped.
 4. Adriving device for a motor driven snow vehicle as set forth in claim 2wherein each of said spring means is swingably suspended from saidtransverse shaft.
 5. A driving device for a motor driven snow vehicle asset forth in claim 2 wherein each of said spring means comprises abow-shaped leaf spring.